WO2013011905A1

WO2013011905A1 - Charging stand, battery pack and charging stand, and battery pack

Info

Publication number: WO2013011905A1
Application number: PCT/JP2012/067765
Authority: WO
Inventors: 洋由山本; 真一板垣; 玉井　幹隆
Original assignee: 三洋電機株式会社
Priority date: 2011-07-15
Filing date: 2012-07-12
Publication date: 2013-01-24
Also published as: JPWO2013011905A1

Abstract

[Problem] To provide a charging stand where foreign bodies such as metal can be detected. [Solution] In the charging stand (10), charging is effected with a battery pack unit (50A) that incorporates a battery (52) that is charged with power delivered to a power-receiving coil (51), or the battery pack (50A) is charged in a condition mounted on a battery-incorporating appliance (50). This charging stand is provided with a power delivery coil (11) that is connected with an AC power source (12) so as to deliver an EMF to the power-receiving coil (51). The AC power source (12) comprises a control circuit (80) having a transmission efficiency detection section (84) that detects the efficiency of transmission of power to the battery-incorporating appliance (50). The control circuit (80) compares the aforementioned transmission efficiency with a prescribed value and thereby determines whether a foreign body is present between the charging stand and the battery-incorporating appliance (50) or battery pack (50A). This prescribed value may depend on mounting information indicating the type thereof; i.e. whether the battery pack (50A) is a single unit or is in a condition mounted on an appliance casing (50B), and/or may depend on the magnitude of the charging current.

Description

Charging stand, battery pack and charging stand, and battery pack

The present invention relates to a charging stand on which a battery built-in device such as a battery pack or a mobile phone is placed on top and the power is transferred by electromagnetic induction to charge the built-in battery.

A charging stand has been developed that carries power from the power transmission coil to the power receiving coil by the action of electromagnetic induction and charges the internal battery. This charging stand incorporates a power transmission coil that is excited by an AC power source. A battery built-in device such as a battery pack or a portable device set on a charging base has a power receiving coil that is electromagnetically coupled to a power transmission coil of the charging base. The battery built-in device also has a built-in circuit for rectifying the alternating current induced in the power receiving coil and supplying the battery to the battery for charging. According to this structure, the battery pack can be charged in a non-contact state by placing the battery pack on the charging stand.

The above charging stand can be conveniently used by moving the power transmission coil to the position of the power reception coil. This is because the user can set the battery built-in device at a free position on the charging stand and charge the power receiving coil of the battery built-in device close to the power receiving coil. A charging stand has been developed to achieve this. (See Patent Document 1)

The transmission efficiency in a state where power is transferred from the power transmission coil to the power reception coil by magnetic induction varies depending on the structure of the power reception coil of the battery built-in device, the resonance frequency, the coupling ratio between the power transmission coil and the power reception coil, the frequency of the power transmission coil, and the like. In order to improve the transmission efficiency, a method of adjusting the frequency of the AC power supplied to the power transmission coil has been developed. (See Patent Document 2)

JP 2009-247194 A JP 2010-104203 A

The charging base of Patent Document 1 described above includes a moving mechanism that moves the power transmission coil so as to approach the power reception coil, and can efficiently transmit power from the power transmission coil to the power reception coil. However, if a conductive or insulating foreign material such as metal is interposed between the power transmission coil and the power reception coil, there is a problem because the efficiency of transmitting power is deteriorated. Therefore, in such non-contact charging, it is important to detect intervening foreign matter.

The present invention was developed for the purpose of solving such problems. An important object of the present invention is to provide a charging stand that can detect foreign matter.

Means for Solving the Problems and Effects of the Invention

The charging stand of the present invention charges the battery pack 50 A by itself with the battery 52 A containing the battery 52 charged by the power conveyed to the power receiving coil 51, or charges the battery pack 50 A while attached to the battery built-in device 50. This is a charging stand 10. The charging stand includes a power transmission coil 11 that is connected to the AC power source 12 and that conveys electromotive force to the power receiving coil 51. The AC power supply 12 includes a control circuit 80 having a transmission efficiency detection unit 84 that detects transmission efficiency for carrying power to the battery built-in device 50. In the control circuit 80, the transmission efficiency is compared with a predetermined value, and a charging stand And whether or not there is a foreign object between the battery built-in device 50 or the battery pack 50A, and the predetermined value is a type indicating whether the battery pack 50A is a single unit or is attached to the device main body 50B. It is a predetermined value depending on the mounting information to be shown and / or depending on the magnitude of the charging current value.
The charging base described above can have an appropriate predetermined value according to the mounting information because the predetermined value depends on the mounting information, for example, the predetermined value is different. Moreover, since it is a predetermined value depending on the magnitude of the charging current value, for example, the predetermined value is different for each charging current value range, an appropriate predetermined value corresponding to the charging current value can be obtained. Therefore, the foreign object can be properly determined and detected.

Moreover, the charging stand of this invention determines with the control circuit 80 that a foreign material exists between a charging stand and the battery built-in apparatus 50 or the battery pack 50A, when transmission efficiency is below a predetermined value.
The above charging stand can determine that there is a foreign object between the charging stand and the battery built-in device 50 or the battery pack 50A due to such a change in transmission efficiency.

In the charging stand of the present invention, the transmission efficiency detection unit 84 multiplies the power consumption or current value and voltage value consumed by the AC power supply 12 and the charging power or current and voltage for charging the battery 52 of the battery built-in device 50. The transmission efficiency can be detected from the ratio of the charging power to the power consumption.
The above charging stand has a feature that the transmission efficiency detection unit can detect the transmission efficiency more accurately.

In the charging stand of the present invention, the charging current value measured in the battery pack 50A and the predetermined value depending on the magnitude of the charging current value are also transmitted from the battery pack 50A to the charging stand.
The charging stand described above is simple because there is no work such as calculating and calculating a predetermined value on the charging stand 10 side, thereby reducing the configuration and work load in the charging stand 10.

In the charging stand of the present invention, a predetermined value depending on the mounting information and the magnitude of the charging current value is transmitted from the pack battery 50A to the charging stand together with the charging current value measured in the battery pack 50A.
The charging stand described above is simple because there is no work such as calculating and calculating a predetermined value on the charging stand 10 side, thereby reducing the configuration and work load in the charging stand 10.

In the charging stand of the present invention, the control circuit 80 compares the transmission efficiency with a predetermined value to determine whether there is a foreign object between the charging stand and the battery built-in device 50 or the battery pack 50A, and stops charging. To do.
The above charging stand can be charged efficiently by preventing charging from being continued in a state where transmission efficiency is reduced due to the space due to the foreign matter, and it is also possible to increase the safety by preventing the metallic foreign matter from becoming hot. be able to.

The battery pack and the charging stand of the present invention include a battery pack 50A attached to the battery built-in device 50 and a battery stand that charges the battery pack 50A in a state of being charged with the battery pack 50A alone or attached to the battery built-in device 50. 10, and depending on the mounting information indicating the type of whether the battery pack 50 A is a single unit or mounted on the battery-powered device 50, and / or depends on the magnitude of the charging current value A battery pack 50A that stores a predetermined efficiency value, and is a charging base 10 of a battery built-in device 50 that includes a battery 52 that is charged by the power carried by the power receiving coil 51, and is connected to the AC power source 12. The power receiving coil 51 includes a power transmission coil 11 that conveys electromotive force, and the AC power source 12 includes a transmission efficiency detection unit (84) that detects transmission efficiency of power transmission to the battery-equipped device 50. A control circuit 80, wherein the control circuit 80 compares the transmission efficiency with the predetermined value to determine whether a foreign object exists between the charging base 10 and the battery-equipped device 50 or the battery pack 50A. It is characterized by.
The above battery pack and charging stand can be set to appropriate predetermined values according to the mounting information because the predetermined values depend on the mounting information, for example, the predetermined values are different. Moreover, since it is a predetermined value depending on the magnitude of the charging current value, for example, the predetermined value is different for each charging current value range, an appropriate predetermined value corresponding to the charging current value can be obtained. Therefore, the foreign object can be properly determined and detected.

The battery pack of the present invention is a battery pack 50A attached to the battery built-in device 50, and is charged by the charging stand 10 alone, or the battery pack 50A is charged while attached to the battery built-in device 50. And a battery pack (52) that is connected to the AC power supply 12 and is charged by the power carried by the power receiving coil 51 by the charging stand 10 including the power transmitting coil 11 that carries the electromotive force to the power receiving coil 51. The battery 50 A is charged, and the AC power supply 12 of the charging stand 10 includes a control circuit 80 having a transmission efficiency detection unit 84 that detects transmission efficiency for conveying power to the battery built-in device 50. In the control circuit 80, the transmission In order to compare the efficiency with a predetermined value and determine whether there is a foreign object between the charging base 10 and the battery built-in device 50 or the battery pack 50A, the battery pack The transmission efficiency depends on the mounting information indicating the type of whether the battery pack 50A is a single unit or is mounted on the battery-powered device 50 in 50A, and / or the transmission efficiency depends on the magnitude of the charging current value. The predetermined value is stored.
The battery pack described above can have an appropriate predetermined value according to the mounting information because the predetermined value depends on the mounting information, for example, the predetermined value is different. Moreover, since it is a predetermined value depending on the magnitude of the charging current value, for example, the predetermined value is different for each charging current value range, an appropriate predetermined value corresponding to the charging current value can be obtained. Therefore, the foreign object can be properly determined and detected.

In the battery pack of the present invention, the charging current value measured in the battery pack 50A and a predetermined value depending on the magnitude of the charging current value are also transmitted from the battery pack 50A to the charging stand.
The charging stand described above is simple because there is no work such as calculating and calculating a predetermined value on the charging stand 10 side, thereby reducing the configuration and work load in the charging stand 10.

In the battery pack of the present invention, together with the charging current value measured in the battery pack 50A, a predetermined value that depends on the mounting information and depends on the magnitude of the charging current value is also transmitted from the battery pack 50A to the charging stand.
The charging stand described above is simple because there is no work such as calculating and calculating a predetermined value on the charging stand 10 side, thereby reducing the configuration and work load in the charging stand 10.

It is a schematic perspective view of the charging stand concerning one Example of this invention. It is a schematic block diagram of the charging stand concerning one Example of this invention. It is a vertical longitudinal cross-sectional view of the charging stand shown in FIG. It is a vertical cross-sectional view of the charging stand shown in FIG. It is a circuit diagram which shows the position detection controller of the charging stand concerning one Example of this invention. It is a block diagram of the charging stand and battery built-in apparatus concerning one Example of this invention. It is the schematic which shows the state which the position detection coil shown in FIG. 5 overlaps. It is a figure which shows an example of the echo signal output from the receiving coil excited with the pulse signal. It is a circuit diagram which shows the position detection controller of the charging stand concerning the other Example of this invention. It is a figure which shows the level of the echo signal induced | guided | derived to the position detection coil of the position detection controller shown in FIG. It is a graph which shows the characteristic which the charging power and transmission efficiency of a battery change with respect to the frequency of the alternating current supplied to a power transmission coil. It is sectional drawing which shows the state which mounted the battery pack single-piece | unit on the charging stand. It is sectional drawing which shows a mode that it mounts in the state which mounted | wore the battery drive apparatus with the battery pack on the charging stand. It is a graph which shows the predetermined value of the threshold value for every charging current value range by whether a pack battery is single.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. However, the embodiment described below exemplifies a charging stand for embodying the technical idea of the present invention, and the present invention does not specify the charging stand as follows. In addition, the member shown by the claim is not what specifies the member of embodiment. In particular, the dimensions, materials, shapes, relative arrangements, and the like of the constituent members described in the embodiments are not intended to limit the scope of the present invention only to the description unless otherwise specified. It is just an example. Note that the size, positional relationship, and the like of the members shown in each drawing may be exaggerated for clarity of explanation. Furthermore, in the following description, the same name and symbol indicate the same or the same members, and detailed description thereof will be omitted as appropriate. Furthermore, each element constituting the present invention may be configured such that a plurality of elements are constituted by the same member and the plurality of elements are shared by one member, and conversely, the function of one member is constituted by a plurality of members. It can also be realized by sharing. In addition, the contents described in some examples and embodiments may be used in other examples and embodiments.

1 to 6 show a schematic configuration diagram and a principle diagram of a charging stand. As shown in FIGS. 1 and 6, the charging stand 10 places the battery built-in device 50 on the charging stand 10 and charges the built-in battery 52 of the battery built-in device 50 by magnetic induction. The battery built-in device 50 includes a power receiving coil 51 that is electromagnetically coupled to the power transmitting coil 11. A battery 52 that is charged with electric power induced in the power receiving coil 51 is incorporated. Here, the battery built-in device 50 includes a battery pack 50A and a device main body 50B to which the battery is mounted. .
Then, as the battery built-in device 50, the battery pack 50A can be charged with the battery pack 50A attached to the device main body 50B, and the battery pack 50A can be charged with the battery pack 50A removed from the device main body 50B.

FIG. 6 shows a circuit diagram of the battery built-in device 50. The battery built-in device 50 has a capacitor 53 connected in parallel with the power receiving coil 51. The capacitor 53 and the power receiving coil 51 constitute a parallel resonance circuit 54. The battery built-in device 50 of FIG. 6 includes a rectifier circuit 57 including a diode 55 that rectifies an alternating current output from the power receiving coil 51, a smoothing capacitor 56 that smoothes the rectified pulsating current, and an output from the rectifier circuit 57. And a charge control circuit 58 for charging the battery 52 with a direct current. The charge control circuit 58 detects the full charge of the battery 52 and transmits a full charge signal indicating that the battery 52 is fully charged to the charging stand 10. The charging stand 10 detects a full charge signal and stops charging.

As shown in FIGS. 1 to 6, the charging stand 10 includes a power transmission coil 11 that is connected to an AC power source 12 and conveys power to the power receiving coil 51, and the power transmission coil 11. A case 20 having an upper surface plate 21 on which the power receiving coil 51 is mounted, a moving mechanism 13 that is built in the case 20 and moves the power transmission coil 11 along the inner surface of the upper surface plate 21 to approach the power receiving coil 51, and the upper surface plate 21. And a position detection controller 14 that detects the position of the battery built-in device 50 to be mounted and controls the moving mechanism 13 to bring the power transmission coil 11 closer to the power receiving coil 51 of the battery built-in device 50. The charging stand 10 includes a power transmission coil 11, an AC power source 12, a moving mechanism 13, and a position detection controller 14 in a case 20.

The charging stand 10 charges the built-in battery 52 of the battery built-in device 50 by the following operation.
(1) When the battery built-in device 50 is placed on the upper surface plate 21 of the case 20, the position detection controller 14 detects the position of the battery built-in device 50.
(2) The position detection controller 14 that has detected the position of the battery built-in device 50 controls the moving mechanism 13 to move the power transmission coil 11 along the upper surface plate 21 with the moving mechanism 13, thereby Approach the power receiving coil 51.
(3) The power transmission coil 11 approaching the power reception coil 51 is electromagnetically coupled to the power reception coil 51 and carries AC power to the power reception coil 51.
(4) The battery built-in device 50 rectifies the AC power of the power receiving coil 51 and converts it into direct current, and charges the built-in battery 52 with this direct current.

The charging stand 10 that charges the battery 52 of the battery built-in device 50 through the above operation has the power transmission coil 11 connected to the AC power supply 12 built in the case 20. The power transmission coil 11 is disposed below the upper surface plate 21 of the case 20 and is disposed so as to move along the upper surface plate 21. The efficiency of power transfer from the power transmission coil 11 to the power reception coil 51 can be improved by bringing the power transmission coil 11 closer to the power reception coil 51. Therefore, the power transmission coil 11 is disposed below the top plate 21 and as close to the top plate 21 as possible. Since the power transmission coil 11 moves so as to approach the power reception coil 51 of the battery built-in device 50 placed on the upper surface plate 21, the power transmission coil 11 is disposed so as to be movable along the lower surface of the upper surface plate 21.

The case 20 containing the power transmission coil 11 is provided with a flat top plate 21 on which the battery built-in device 50 is placed on the top surface. The charging stand 10 shown in the figure is disposed horizontally with the entire top plate 21 as a flat surface. The upper surface plate 21 has such a size that various battery built-in devices 50 having different sizes and outer shapes can be placed thereon, for example, a quadrangle having a side of 5 cm to 30 cm, or a circle having a diameter of 5 cm to 30 cm. The charging stand according to the present invention can also charge a built-in battery in order by placing a plurality of battery-equipped devices together so that the top plate is enlarged, that is, a size that allows a plurality of devices with a built-in battery to be loaded simultaneously. . The top plate can also be provided with a peripheral wall around it, and a battery built-in device can be set inside the peripheral wall to charge the built-in battery.

The power transmission coil 11 is wound in a spiral shape on a surface parallel to the upper surface plate 21 and radiates an alternating magnetic flux above the upper surface plate 21. The power transmission coil 11 radiates an alternating magnetic flux orthogonal to the upper surface plate 21 above the upper surface plate 21. The power transmission coil 11 is supplied with AC power from the AC power source 12 and radiates AC magnetic flux above the upper surface plate 21. The power transmission coil 11 can increase the inductance by winding a wire around a core 15 made of a magnetic material. The core 15 is made of a magnetic material such as ferrite having a high magnetic permeability, and has a bowl shape that opens upward. The bowl-shaped core 15 has a shape in which a columnar portion 15A disposed at the center of a power transmission coil 11 wound in a spiral shape and a cylindrical portion 15B disposed on the outside are connected at the bottom. The power transmission coil 11 having the core 15 can concentrate the magnetic flux to a specific portion and efficiently transmit power to the power reception coil 51. However, the power transmission coil does not necessarily need to be provided with a core, and may be an air-core coil. Since the air-core coil is light, a moving mechanism for moving it on the inner surface of the upper plate can be simplified. The power transmission coil 11 is substantially equal to the outer diameter of the power reception coil 51 and efficiently conveys power to the power reception coil 51.

The AC power supply 12 supplies, for example, high frequency power of 20 kHz to 1 MHz to the power transmission coil 11. The AC power supply 12 is connected to the power transmission coil 11 via a flexible lead wire 16. This is because the power transmission coil 11 is moved so as to approach the power reception coil 51 of the battery built-in device 50 placed on the upper surface plate 21. Although not shown, the AC power supply 12 includes an oscillation circuit and a power amplifier that amplifies the AC output from the oscillation circuit.

The power transmission coil 11 is moved by the moving mechanism 13 so as to approach the power reception coil 51. The moving mechanism 13 in FIGS. 1 to 4 moves the power transmission coil 11 along the upper surface plate 21 in the X-axis direction and the Y-axis direction to approach the power receiving coil 51. The moving mechanism 13 shown in the figure rotates the screw rod 23 by the servo motor 22 controlled by the position detection controller 14 to move the nut member 24 screwed into the screw rod 23, thereby moving the power transmission coil 11 to the power receiving coil 51. To approach. The servo motor 22 includes an X-axis servo motor 22A that moves the power transmission coil 11 in the X-axis direction, and a Y-axis servo motor 22B that moves the Y-axis direction. The screw rod 23 includes a pair of X-axis screw rods 23A that move the power transmission coil 11 in the X-axis direction, and a Y-axis screw rod 23B that moves the power transmission coil 11 in the Y-axis direction. The pair of X-axis screw rods 23A are arranged in parallel to each other, driven by the belt 25, and rotated together by the X-axis servomotor 22A. The nut member 24 includes a pair of X-axis nut members 24A screwed into the respective X-axis screw rods 23A and a Y-axis nut member 24B screwed into the Y-axis screw rods 23B. The Y-axis screw rod 23B is coupled so that both ends thereof can rotate to the pair of X-axis nut members 24A. The power transmission coil 11 is connected to the Y-axis nut member 24B.

Furthermore, the moving mechanism 13 shown in the figure has a guide rod 26 disposed in parallel with the Y-axis screw rod 23B in order to move the power transmission coil 11 in the Y-axis direction in a horizontal posture. Both ends of the guide rod 26 are connected to the pair of X-axis nut members 24A and move together with the pair of X-axis nut members 24A. The guide rod 26 penetrates the guide portion 27 coupled to the power transmission coil 11 so that the power transmission coil 11 can be moved along the guide rod 26 in the Y-axis direction. That is, the power transmission coil 11 moves in the Y-axis direction in a horizontal posture via the Y-axis nut member 24 B and the guide portion 27 that move along the Y-axis screw rod 23 B and the guide rod 26 arranged in parallel to each other. To do.

In the moving mechanism 13, when the X-axis servo motor 22A rotates the X-axis screw rod 23A, the pair of X-axis nut members 24A move along the X-axis screw rod 23A, and the Y-axis screw rod 23B and the guide rod 26 is moved in the X-axis direction. When the Y-axis servo motor 22B rotates the Y-axis screw rod 23B, the Y-axis nut member 24B moves along the Y-axis screw rod 23B, and moves the power transmission coil 11 in the Y-axis direction. At this time, the guide part 27 connected to the power transmission coil 11 moves along the guide rod 26 to move the power transmission coil 11 in the Y-axis direction in a horizontal posture. Therefore, the rotation of the X-axis servomotor 22A and the Y-axis servomotor 22B can be controlled by the position detection controller 14, and the power transmission coil 11 can be moved in the X-axis direction and the Y-axis direction. However, the charging stand of the present invention does not specify the moving mechanism as the above mechanism. This is because any mechanism that can move the power transmission coil in the X-axis direction and the Y-axis direction can be used as the moving mechanism.

Furthermore, the charging stand of the present invention does not specify the moving mechanism as a mechanism that moves the power transmission coil in the X-axis direction and the Y-axis direction. That is, the charging stand of the present invention has a structure in which a linear guide wall is provided on the upper plate, and a battery built-in device is placed along the guide wall, and the power transmission coil can be moved linearly along the guide wall. Because it can be done. Although this charging stand is not shown, the power transmission coil can be moved linearly along the guide wall as a moving mechanism that can move the power transmission coil only in one direction, for example, the X-axis direction.

The position detection controller 14 detects the position of the battery built-in device 50 placed on the top plate 21. The position detection controller 14 in FIGS. 1 to 4 detects the position of the power receiving coil 51 built in the battery built-in device 50, and causes the power transmitting coil 11 to approach the power receiving coil 51.

As shown in FIG. 5, the position detection controller 14 generates a plurality of position detection coils 30 fixed to the inner surface of the upper surface plate 21, and generates a detection pulse for supplying a pulse signal as a position detection signal to the position detection coil 30. A receiving circuit 32 that receives an echo signal that is excited by a pulse of a position detection signal supplied from the detection pulse generation circuit 31 to the position detection coil 30 and is output from the power receiving coil 51 to the position detection coil 30; And an identification circuit 33 for determining the position of the power receiving coil 51 from the echo signal received by the receiving circuit 32.

The position detection coil 30 is composed of a plurality of rows of coils, and the plurality of position detection coils 30 are arranged on the back side of the top plate 21. The position detection coil 30 is fixed to the inner surface of the upper surface plate 21 and can be disposed on the back side of the upper surface plate 21. The position detection coil 30 includes a plurality of X-axis position detection coils 30A that detect the position of the power receiving coil 51 in the X-axis direction, and a plurality of Y-axis position detection coils 30B that detect a position in the Y-axis direction. The X-axis position detection coil 30A has a loop shape elongated in the Y-axis direction, and the plurality of X-axis position detection coils 30A are fixed to the inner surface of the upper surface plate 21 at a predetermined interval. The Y-axis position detection coil 30B has a loop shape elongated in the X-axis direction, and the plurality of Y-axis position detection coils 30B are fixed to the inner surface of the upper surface plate 21 at a predetermined interval.

The position detection coil 30 is arranged such that a part of the position detection coil 30 disposed adjacent to the position detection coil 30 is overlapped. The position detection coil 30 of the elongated coil is displaced in a direction orthogonal to the longitudinal direction of the coil, and the adjacent position detection coils 30 are arranged so as to overlap each other. The X-axis position detection coil 30A has an elongated loop shape having a linear portion extending in the Y-axis direction, and the plurality of X-axis position detection coils 30A are displaced in the X-axis direction by a predetermined amount of overlap. It arrange | positions on the back side of the upper surface plate 21 so that it may become (d). The Y-axis position detection coil 30B has an elongated loop shape having a linear portion extending in the X-axis direction, and the plurality of Y-axis position detection coils 30B are displaced in the Y-axis direction by a predetermined amount of overlap. It arrange | positions on the back side of the upper surface plate 21 so that it may become (d).

In the position detection coil 30 of FIG. 5, the overlapping amount (d) between the position detection coils 30 adjacent to each other so as to overlap each other is 2/3 of the lateral width (W) of the elongated coil. In other words, the position detection coils 30 adjacent to each other are arranged so as to be displaced in the lateral width direction of the coil by 1/3 of the lateral width (W) of the coil. As shown in FIG. 7, the position detection coil 30 has an area where two adjacent position detection coils 30 overlap each other with 2/3 of each position detection coil 30 (hatching A and hatching B in FIG. 7). The area where the three position detection coils 30 adjacent to each other overlap each other is a 1/3 area of each position detection coil 30 (the common part of hatching A and hatching B in FIG. 7). In the illustrated position detection coil 30, the overlapping amount (d) between adjacent position detection coils 30 is 2/3 of the width (W) of the elongated coil, but the position detection coils are adjacent to each other so as to overlap each other. The overlap amount (d) between the position detection coils can be set to 1/2 to 9/10 of the lateral width (W) of the elongated coil.

A position detection coil in which the overlap amount (d) between adjacent position detection coils so as to overlap each other is ½ of the lateral width (W) of the coil is not shown, but two adjacent position detection coils overlap each other. The area is a half of each position detection coil. A position detection coil in which the overlap amount (d) between adjacent position detection coils so as to overlap each other is 3/4 of the lateral width (W) of the coil is not shown, but two adjacent position detection coils are not shown. The overlapping area of each position detection coil becomes a 3/4 area, and the overlapping area of the three position detection coils adjacent to each other becomes a 2/4 area of each position detection coil, and the four position detections adjacent to each other. A region where the coils overlap is a quarter of each position detection coil.

Further, the lateral width (W) of the position detection coil 30 is substantially equal to the outer diameter (D) of the power receiving coil 51, or is larger than the outer diameter (D), or is smaller than the outer diameter (D). is doing. The position detection coil 30 can detect the position of the power receiving coil 51 with higher accuracy by narrowing the center interval (d).

The detection pulse generation circuit 31 outputs a pulse signal to the position detection coil 30 at a predetermined timing. The position detection coil 30 to which the pulse signal is input excites the power receiving coil 51 that approaches with the pulse signal. The excited power receiving coil 51 outputs an echo signal to the position detection coil 30 with the energy of the flowing current. Therefore, as shown in FIG. 8, the position detection coil 30 near the power receiving coil 51 induces an echo signal from the power receiving coil 51 with a predetermined time delay after the pulse signal is input. The echo signal induced in the position detection coil 30 is output from the reception circuit 32 to the identification circuit 33.

The identification circuit 33 determines whether or not the power receiving coil 51 is approaching the position detection coil 30 using the echo signal input from the receiving circuit 32. When echo signals are induced in the plurality of position detection coils 30, the identification circuit 33 determines that the position detection coil 30 with the highest echo signal level is closest.

The position detection controller 14 shown in FIG. 5 connects each position detection coil 30 to the reception circuit 32 via the switching circuit 34. Since the position detection controller 14 switches the inputs in order and connects them to the plurality of position detection coils 30, the single reception circuit 32 can detect the echo signals of the plurality of position detection coils 30. However, an echo signal can also be detected by connecting a receiving circuit to each position detection coil.

The position detection controller 14 shown in FIG. 5 connects the plurality of position detection coils 30 in order with the switching circuit 34 controlled by the identification circuit 33 and connects to the receiving circuit 32. The detection pulse generation circuit 31 is connected to the output side of the switching circuit 34 and outputs a pulse signal to the position detection coil 30. The level of the pulse signal output from the detection pulse generation circuit 31 to the position detection coil 30 is extremely higher than the echo signal from the power receiving coil 51. The receiving circuit 32 has a limiter circuit 35 made of a diode connected to the input side. The limiter circuit 35 limits the signal level of the pulse signal input from the detection pulse generation circuit 31 to the reception circuit 32 and inputs the pulse signal to the reception circuit 32. An echo signal having a low signal level is input to the receiving circuit 32 without being limited. The receiving circuit 32 amplifies and outputs both the pulse signal and the echo signal. The echo signal output from the receiving circuit 32 is a predetermined timing from the pulse signal, for example, several μsec.
The signal is delayed by several hundred μsec. Since the delay time that the echo signal is delayed from the pulse signal is a fixed time, the signal after a predetermined delay time from the pulse signal is used as an echo signal, and the receiving coil 51 approaches the position detection coil 30 from the level of this echo signal. Determine whether or not.

The receiving circuit 32 is an amplifier that amplifies and outputs an echo signal input from the position detection coil 30. The receiving circuit 32 outputs a pulse signal and an echo signal. The identification circuit 33 determines whether or not the power reception coil 51 is set close to the position detection coil 30 from the pulse signal and echo signal input from the reception circuit 32. The identification circuit 33 includes an A / D converter 36 that converts a signal input from the reception circuit 32 into a digital signal. The digital signal output from the A / D converter 36 is calculated to detect an echo signal. The identification circuit 33 detects a signal input after a specific delay time from the pulse signal as an echo signal, and further determines whether the power receiving coil 51 is approaching the position detection coil 30 from the level of the echo signal.

The identification circuit 33 detects the position of the power receiving coil 51 in the X-axis direction by controlling the switching circuit 34 so that the plurality of X-axis position detection coils 30A are sequentially connected to the receiving circuit 32. Each time the identification circuit 33 connects each X-axis position detection coil 30A to the reception circuit 32, the identification circuit 33 outputs a pulse signal to the X-axis position detection coil 30A connected to the identification circuit 33, and a specific delay from the pulse signal. Whether or not the receiving coil 51 is approaching the X-axis position detection coil 30A is determined based on whether or not an echo signal is detected after the time. The identification circuit 33 connects all the X-axis position detection coils 30A to the reception circuit 32, and determines whether or not the power receiving coils 51 are close to the respective X-axis position detection coils 30A. When the power receiving coil 51 approaches one of the X-axis position detection coils 30A, an echo signal is detected in a state where the X-axis position detection coil 30A is connected to the reception circuit 32. Therefore, the identification circuit 33 can detect the position of the power receiving coil 51 in the X-axis direction from the X-axis position detection coil 30A that can detect an echo signal. In a state in which the power receiving coil 51 approaches across the plurality of X-axis position detection coils 30A, echo signals are detected from the plurality of X-axis position detection coils 30A. In this state, the identification circuit 33 determines the position of the power receiving coil 51 in the X-axis direction from the level of echo signals induced in the plurality of X-axis position detection coils 30A. Further, the identification circuit 33 similarly controls the Y-axis position detection coil 30Y to detect the position of the power receiving coil 51 in the Y-axis direction.

The identification circuit 33 controls the moving mechanism 13 from the position in the X axis direction and the position in the Y axis direction to be detected, and moves the power transmission coil 11 to a position approaching the power reception coil 51. The identification circuit 33 controls the X-axis servomotor 22 A of the moving mechanism 13 to move the power transmission coil 11 to the position of the power reception coil 51 in the X-axis direction. Further, the Y-axis servomotor 22B of the moving mechanism 13 is controlled to move the power transmission coil 11 to the position of the power reception coil 51 in the Y-axis direction.

As described above, the position detection controller 14 moves the power transmission coil 11 to a position approaching the power reception coil 51. The charging stand of the present invention can charge the battery 52 by transferring power from the power transmission coil 11 to the power reception coil 51 after the power transmission coil 11 approaches the power reception coil 51 by the position detection controller 14. However, the charging stand further accurately controls the position of the power transmission coil 11 to approach the power receiving coil 51, and then transports power to charge the battery 52.

Further, the position detection controller 64 shown in FIG. 9 causes the discrimination circuit 73 to detect the level of the echo signal induced in each position detection coil 30 with respect to the position of the power receiving coil 51, that is, each position as shown in FIG. A memory circuit 77 is provided for storing the level of an echo signal that is induced after a predetermined time has elapsed by exciting the detection coil 30 with a pulse signal. The position detection controller 64 detects the level of the echo signal induced in each position detection coil 30, compares the level of the detected echo signal with the level of the echo signal stored in the storage circuit 77, and The position of the power receiving coil 51 is detected.

The position detection controller 64 obtains the position of the power receiving coil 51 from the level of the echo signal induced in each position detection coil 30 as follows. FIG. 10 shows the level of the echo signal induced in the X-axis position detection coil 30A in a state where the power receiving coil 51 is moved in the X-axis direction, and the horizontal axis shows the position of the power receiving coil 51 in the X-axis direction. The vertical axis indicates the level of the echo signal induced in each X-axis position detection coil 30A. The position detection controller 64 detects the level of the echo signal induced in each X-axis position detection coil 30A, and obtains the position of the power receiving coil 51 in the X-axis direction. As shown in this figure, when the power receiving coil 51 is moved in the X-axis direction, the level of the echo signal induced in each X-axis position detection coil 30A changes.

For example, when the power receiving coil 51 is located between the first X-axis position detection coil 30A and the second X-axis position detection coil 30A, as shown by a point a in FIG. 10, the first X-axis position detection coil 30A. And the level of the echo signal induced in the second X-axis position detection coil 30A is the maximum and the same. Further, when the power receiving coil 51 is at a position deviated from the middle between the first X-axis position detection coil 30A and the second X-axis position detection coil 30A, the first X-axis position detection coil 30A and the second X-axis position The level ratio of the echo signal induced in the detection coil 30A changes. Therefore, the position of the power receiving coil 51 can be detected from the level ratio of echo signals induced in the first X-axis position detection coil 30A and the second X-axis position detection coil 30A.

Furthermore, when the power receiving coil 51 is in the center of the second X-axis position detection coil 30A, that is, in the area A in FIG. 10, the level of the echo signal induced in the second X-axis position detection coil 30A is , Become the strongest. However, when the power receiving coil 51 is in the A region, the level variation of the echo signal with respect to the movement distance of the power receiving coil 51 in the X-axis direction is small, and the level of the echo signal varies depending on other factors. When 51 is in the A region, if the position of the power receiving coil 51 is determined only by the level of the echo signal induced in the second X-axis position detection coil 30A, it cannot be accurately determined. Therefore, when the identification circuit 33 is in this region, the first X-axis position detection coil 30A and the third X-axis position detection coil as well as the echo signal induced by the second X-axis position detection coil 30A The position of the power receiving coil 51 is also determined from the level of the echo signal induced by 30A. When the power receiving coil 51 is located at the center of the second X-axis position detection coil 30A, the levels of the echo signals induced in the first X-axis position detection coil 30A and the third X-axis position detection coil 30A are equal. Alternatively, the level of the echo signal becomes 0 level. Accordingly, the identification circuit 33 is applied to the first X-axis position detection coil 30A and the third X-axis position detection coil 30A in a state where the echo signal induced in the second X-axis position detection coil 30A is at the maximum level. If the levels of the induced echo signals are equal or both are 0 level, it is determined that the power receiving coil 51 is located at the center of the second X-axis position detection coil 30A. When the position of the power receiving coil 51 is slightly shifted from the center portion of the second X-axis position detection coil 30A, an echo signal that is induced in the first X-axis position detection coil 30A and the third X-axis position detection coil 30A. The level of changes. When the power receiving coil 51 is displaced toward the first X-axis position detection coil 30A, the level of the echo signal induced in the first X-axis position detection coil 30A is induced in the third X-axis position detection coil 30A. It becomes larger than the level of the echo signal. Therefore, in this state, the identification circuit 33 accurately detects the position of the power receiving coil 51 from the level ratio of echo signals induced in the first X-axis position detection coil 30A and the second X-axis position detection coil 30A. can do. This is because as the power receiving coil 51 moves toward the first X-axis position detection coil 30A, the level of the echo signal induced in the first X-axis position detection coil 30A increases. On the other hand, when the power receiving coil 51 is shifted to the third X-axis position detection coil 30A side, the level of the echo signal induced in the third X-axis position detection coil 30A is changed to the first X-axis position detection coil 30A. It becomes larger than the level of the induced echo signal. Therefore, in this state, the identification circuit 33 can accurately detect the position 51 of the power receiving coil from the level ratio of echo signals induced in the second and third X-axis position detecting coils 30A. This is because as the power receiving coil 51 moves toward the third X-axis position detection coil 30A, the level of the echo signal induced in the third X-axis position detection coil 30A increases.

As described above, the identification circuit 33 does not determine the position of the power receiving coil 51 only from the echo signal of the position detection coil 30 at the maximum level in a state where the echo signal is at the maximum level. The position of the power receiving coil 51 is determined in consideration of echo signals induced in the position detection coils 30 on both sides of the position detection coil 30 that detects the maximum level echo signal. Accordingly, the position of the power receiving coil 51 in the area A, which is the central portion of the position detection coil 30, can accurately detect even a slight deviation from the center of the position detection coil 30 at the maximum level.
Note that the identification circuit 33 can also determine the position of the power receiving coil 51 only from the echo signal of the position detection coil 30 at the maximum level when the echo signal is at the maximum level.

The identification circuit 73 stores in the storage circuit 77 the level and level ratio of the echo signal induced in each X-axis position detection coil 30A with respect to the position of the power receiving coil 51 in the X-axis direction. When the power receiving coil 51 is placed, an echo signal is induced in one of the X-axis position detection coils 30A. Therefore, the identification circuit 73 detects that the power receiving coil 51 has been placed by an echo signal induced in the X-axis position detection coil 30 A, that is, that the battery built-in device 50 has been placed on the charging stand 10. Further, the level and level ratio of the echo signal induced in one of the X-axis position detection coils 30 A is compared with the level and level ratio stored in the storage circuit 77, and the position of the power receiving coil 51 in the X-axis direction. Is accurately determined.

The above shows a method in which the identification circuit 73 detects the position of the power receiving coil 51 in the X-axis direction from the echo signal induced in the X-axis position detection coil 30A, but the position of the power receiving coil 51 in the Y-axis direction is also X. In the same manner as in the axial direction, it can be detected from the echo signal induced in the Y-axis position detection coil 30B.

When the identification circuit 73 detects the positions of the power receiving coil 51 in the X-axis direction and the Y-axis direction, the position detection controller 64 moves the power transmission coil 11 to the position of the power receiving coil 51 with the position signal from the identification circuit 73. Let
When the echo signal having the waveform as described above is detected, the identification circuit 73 of the charging stand can recognize and identify that the power receiving coil 51 of the battery built-in device 50 is mounted. When a waveform different from the waveform of the echo signal is detected and identified, the power supply can be stopped assuming that a device other than the power receiving coil 51 (for example, a metal foreign object) of the battery built-in device 50 is mounted. When the waveform of the echo signal is not detected or identified, the power supply coil 51 of the battery built-in device 50 is not mounted and power is not supplied.

The AC power supply 12 includes a frequency adjustment circuit 81 that adjusts the frequency of the AC supplied to the power transmission coil 11 and a control circuit 80 that controls the frequency adjustment circuit 81. 6 also includes an output power adjustment circuit 82 for charging the battery 52 of the battery built-in device 50 with a predetermined power.

The control circuit 80 includes a charging power detection unit 83 that detects charging power for charging the battery 52 of the battery built-in device 50 set on the upper surface plate 21, and a transmission efficiency detection that detects transmission efficiency for carrying power to the battery built-in device 50. The frequency adjustment circuit 81 is controlled by calculating the output frequency of the AC power supply 12 from the charging power of the battery 52 detected by the unit 84 and the charging power detection unit 83 and the transmission efficiency detected by the transmission efficiency detection unit 84. And an arithmetic unit 85.

The above AC power supply 12 controls the frequency adjustment circuit 81 by both the charging power and the transmission efficiency of the battery built-in device 50 and adjusts the frequency of the AC supplied to the power transmission coil 11 by the calculation unit 85 of the control circuit 80. To do. The control circuit 80 specifies the output frequency of the AC power supply 12 by controlling the frequency adjustment circuit 81 so that the transmission efficiency is good and the battery 52 can be charged with a predetermined power. FIG. 11 shows characteristics in which the transmission efficiency and the power for charging the battery 52 are changed by changing the output frequency of the AC power supply 12. As shown in this figure, the frequency at which transmission efficiency is maximized is not the same as the frequency at which charging power is maximized. The frequency that maximizes the transmission efficiency decreases the charging power, while the frequency that maximizes the charging power decreases the transmission efficiency. Therefore, when the output frequency of the AC power supply 12 sets the transmission efficiency to the maximum value, the power for charging the battery 52, that is, the current decreases, and the charging time increases.
Whether the transmission efficiency output from the transmission efficiency detection unit 84 is less than a predetermined value (for example, 50%) at the start of charging or during charging is calculated and determined by the calculation unit 85 of the control circuit 80. Is done. If it is equal to or less than the predetermined value, a stop signal is output from the arithmetic unit 85 to the output power adjustment circuit 82.

The charging stand of the present invention does not charge only a specific battery built-in device. Various types of battery built-in devices are placed on the top plate, and the batteries of a plurality of types of battery built-in devices are charged. The transmission efficiency and charging power with respect to the frequency shown in FIG. 117 vary depending on the battery built-in device. When the battery built-in device 50 is set on the upper surface plate 21, the control circuit 80 changes the frequency of the AC power supply 12 at a predetermined interval or continuously, so that the transmission efficiency detection unit 84 and the charging power detection unit 83 Then, the transmission efficiency and the charging power are detected, and the frequency is set to an optimum value by the calculation unit 85 from the detected transmission efficiency and the charging power.

The control circuit 80 specifies the output frequency as follows.
(1) The frequency is changed, the transmission efficiency detection unit 84 detects the transmission efficiency, and the calculation unit 85 detects the frequency at which the transmission efficiency becomes the maximum value.
(2) The charging power detection unit 83 detects the charging power of the battery 52 by increasing or decreasing the frequency from the frequency at which the transmission efficiency is maximized.
(3) When the frequency is changed and the charging power of the battery 52 reaches the preset power, the calculation unit 85 controls the frequency adjustment circuit 81 so that the output frequency of the AC power supply 12 becomes the frequency. To control.

Further, the control circuit 80 can specify the output frequency as follows.
(1) The frequency is changed, the transmission efficiency detection unit 84 detects the transmission efficiency, and the calculation unit 85 detects the frequency at which the transmission efficiency becomes the maximum value.
(2) The charging power detection unit 83 detects the charging power of the battery 52 by increasing or decreasing the frequency from the frequency at which the transmission efficiency is maximized.
(3) The arithmetic unit 85 controls the frequency adjustment circuit 81 when the frequency is changed and the charging power of the battery 52 does not reach the preset setting power, that is, when the charging power is smaller than the setting power. Then, the output frequency is specified as a frequency that maximizes the charging power.

Further, the control circuit 80 can specify the output frequency as follows.
(1) The frequency is changed, the transmission efficiency detection unit 84 detects the transmission efficiency, and the calculation unit 85 detects the frequency at which the transmission efficiency becomes the maximum value.
(2) The charging power detection unit 83 detects the charging power of the battery 52 by increasing or decreasing the frequency from the frequency at which the transmission efficiency is maximized.
(3) The arithmetic unit 85 controls the frequency adjustment circuit 81 when the charge power of the battery 52 does not become the preset set power by changing the frequency, that is, when the charge power is smaller than the set power. The output frequency is set to the frequency at which the charging power becomes the maximum value, and the output power adjusting circuit 82 is controlled to set the charging power of the battery 52 as the set power.

The charging power detection unit 83 detects both the current and voltage for charging the battery 52 of the battery built-in device 50, or detects the charging current to detect the charging power or current and voltage of the battery 52. 6 receives the signal transmitted from the transmission unit 59 of the battery built-in device 50 by the reception unit 89, and detects the charging power (or current and voltage) of the battery 52. The charging stand 10 detects the full charge of the battery 52 of the battery built-in device 50 and stops charging. Therefore, the receiving part 89 which detects the battery information transmitted from the battery built-in apparatus 50 is provided. The charging power detection unit 83 detects battery information transmitted from the battery built-in device 50, and detects the charging power of the battery 52 by calculating the power from a value obtained by multiplying the current and voltage. The battery information is transmitted from the battery built-in device to the 50 charging base 10 by wireless transmission or by modulation that changes the impedance or load of the power receiving coil 51.

The transmission efficiency detection unit 84 detects the input power of the AC power supply 12 and the charging power for charging the battery 52 of the battery built-in device 50, and detects the transmission efficiency from the ratio of the charging power to the input power. The charging power is detected from the battery information input from the receiving unit 89. The transmission efficiency detector 84 detects the transmission efficiency from the ratio of charging power / input power.

The AC power supply 12 of FIG. 6 includes a rectifier circuit 90 that converts the alternating current of the commercial power 99 that is input into direct current, and a DC / AC inverter that converts the direct current output from the rectifier circuit 90 into alternating current of a predetermined voltage and frequency. 91 is provided. The DC / AC inverter 91 includes a switching element 92 that is switched on and off at a predetermined cycle, and an input circuit 93 that inputs an on / off signal to the switching element 92.

The AC power supply 12 controls the frequency adjustment circuit 81 with the control circuit 80, adjusts the cycle in which the frequency adjustment circuit 81 turns on and off the switching element 92 via the input circuit 93, and adjusts the output frequency of the DC / AC inverter 91. adjust. Further, the output power adjustment circuit 82 controls the output power by controlling the duty for controlling the switching element 92 to be turned on / off via the input circuit 93.
Further, the output power adjustment circuit 82 turns off the switching element 92 via the input circuit 93 by the stop signal from the calculation unit 85 of the control circuit 80 to stop charging.

Further, the control circuit 80 detects the power consumption of the AC power supply 12 by detecting the power consumption of the DC / AC inverter 91 by the input power detection unit 87. The input power detection unit 87 detects the average value of the current flowing through the switching element 92 and the voltage input to the DC / AC inverter 91, and determines the power consumption (consumed current value and voltage value) of the DC / AC inverter 91. (Multiplied value) is detected. DC / AC inverter 9
The power consumption of 1 is comparable to the power consumption of the AC power supply 12. This is because the power efficiency of the rectifier circuit 90 is nearly 100%. The transmission efficiency detector 84 detects the transmission efficiency by detecting the ratio between the power consumption of the DC / AC inverter 91 and the charging power of the battery 52.

The charging base 10 can easily adjust the frequency of the alternating current supplied to the power transmission coil 11 at the timing when the switching element 92 is turned on and off, and in order to detect the transmission efficiency, the power consumption from the input power of the DC / AC inverter 91. Therefore, the power consumption of the AC power supply 12 can be detected easily and accurately. This is because the detection of the DC voltage and current can be made easier than the detection of the AC voltage and current.

Instead of the above embodiment, the battery information can be transmitted to the charging stand 10 as follows.
Instead of the transmission unit 59 in the above embodiment, a battery information detection circuit 59 for detecting battery information of the built-in battery 52 is provided.
Instead of the reception unit 89, a detection circuit 17 (shown by a dotted line in FIG. 6) connected to the power transmission coil 11 is provided.
The battery built-in device 50 is further provided with a modulation circuit 161 (indicated by a dotted line in FIG. 6) that changes the impedance of the power receiving coil 51 based on the battery information of the built-in battery 52, and the charging base 10 is changed by the modulation circuit 161. And a detection circuit 17 that detects battery information by detecting a change in impedance of the power receiving coil 51 via the power transmission coil 11.

The modulation circuit 61 includes a load circuit 162 in which a switching element 164 (shown by a dotted line in FIG. 6) is connected in series to an impedance modulation capacitor 53 connected in parallel to the power receiving coil 51, and switching of the load circuit 162. And a control circuit 165 (shown by a dotted line in FIG. 6) for switching the element 164 on and off with battery information.
The control circuit 165 switches the switching element 164 on and off with the battery information and transmits the battery information to the charging stand 10. The control circuit 165 includes a battery such as a charging battery voltage, a charging current, a battery temperature, a battery serial number, an allowable charging current for specifying the charging current of the battery, and an allowable temperature for controlling the charging of the battery. Information is transmitted as a digital signal by controlling the switching element 164. The battery built-in device 50 includes a battery information detection circuit 59 that detects battery information of the built-in battery 52. With the battery information detection circuit 59, a battery such as a voltage of a charged battery, a charging current, a battery temperature, and the like. Information is detected and input to the control circuit 165.
The control circuit 165 includes a microprocessor unit (MPU), and a memory used for data storage or the like is built in the control circuit 165.
The control circuit 165 transmits battery information by repeating a predetermined cycle, that is, a transmission timing for transmitting battery information and a non-transmission timing for not transmitting battery information at a predetermined cycle. This period is set to, for example, 0.1 sec to 5 sec, preferably 0.1 sec to 1 sec. Since the voltage, current, temperature, etc. of the battery being charged change, such battery information is repeatedly transmitted in the above cycle, but the battery serial number, the allowable charging current for identifying the battery charging current, The battery information such as the allowable temperature for controlling the charging of the battery does not need to be transmitted only at the beginning of charging and then repeatedly transmitted thereafter. At the transmission timing, the modulation circuit 161 switches the switching element 164 on and off with a digital signal indicating the battery information, modulates the parallel capacity of the power receiving coil 51, and transmits the battery information. For example, the control circuit 165 provided in the modulation circuit 161 transmits the battery information by controlling the on / off of the switching element 164 at a speed of 1000 bps. However, the control circuit 165 can also transmit battery information at 500 bps to 5000 bps. After the battery information is transmitted at 1000 bps at the transmission timing, the transmission of the battery information is stopped and the battery is charged in a normal state at the non-transmission timing. At the transmission timing, the switching element 164 is switched on and off. In order to transmit battery information, an impedance modulation capacitor 53 is connected to the power receiving coil 51. Since the impedance modulation capacitor 63 is connected in parallel to the power receiving coil 51, the efficiency of power transfer from the power transmitting coil 11 to the power receiving coil 51 is slightly lower than the designed optimum state. However, the transmission timing is shorter than the non-transmission timing, and the timing at which the impedance modulation capacitor 63 is connected to the power receiving coil 51 is very short even at this transmission timing. Even if the power transfer efficiency is reduced in a state where the capacitor 63 is connected, the reduction in power transfer efficiency can be almost ignored in the total time.

The charging stand 10 detects the impedance change of the power receiving coil 51 from the voltage level change of the power transmission coil 11 and the battery information from the impedance change by the detection circuit 17. When the impedance of the power receiving coil 51 changes, the voltage level of the power transmitting coil 11 changes because the power transmitting coil 11 is electromagnetically coupled to the power receiving coil 51. Since the voltage level of the power transmission coil 11 changes in synchronization with the on / off of the switching element 64, the on / off state of the switching element 64 can be detected from the change in the voltage level of the power transmission coil 11. Since the modulation circuit 161 switches the switching element 64 on and off with a digital signal indicating battery information, the detection circuit 17 detects the digital signal indicating the battery information by detecting the on / off of the switching element 164 and is detected. From the digital signal, the voltage, current, temperature, etc. of the battery being charged can be detected.
Thus, the charging stand 10 periodically receives battery information via the receiving coil 51 and the power transmission coil 11.

However, the detection circuit 17 can also detect battery information from any of change values such as a change in the current level of the power transmission coil 11, a change in phase with respect to the voltage of the current, or a change in transmission efficiency. This is because these characteristics of the power transmission coil 11 change due to the impedance change of the power reception coil 51.

The battery built-in device 50 is connected to the power receiving coil 51, converts alternating current induced in the power receiving coil 51 into direct current, and rectifies the alternating current of the power receiving coil 51, and a rectifier circuit 53 that supplies charging power to the internal battery 52. A series capacitor 155 connected in series to the power receiving coil 51, an impedance modulation capacitor 53 connected in parallel to the power receiving coil 51, a series capacitor 155, the impedance modulation capacitor 53, and the power receiving coil 51 are input to the circuit 53. And a switching element 164 for switching the connection state between the two. When the position detection controller 14 outputs a position detection signal, the battery built-in device 50 connects the impedance modulation capacitor 53 to the power reception coil 51 by the switching element 164, and the power transmission coil 11 to the power reception coil 51. In the state of carrying power, the power receiving coil 51 and the impedance modulation capacitor 53 are disconnected from each other, and the alternating current of the power receiving coil 51 is output to the rectifier circuit 57 via the series capacitor 155.

The battery built-in device 50 and the charging stand 10 constitute a parallel resonance circuit 5457 at all times to accurately detect the position of the power receiving coil 51, and at the time of charging, the impedance modulation capacitor 53 is disconnected to increase power efficiency. The built-in battery 52 can be efficiently charged. The echo signal can be generated because the impedance modulation capacitor 53 is connected in parallel with the power receiving coil 51 in a state where the position of the power receiving coil 51 is detected. The reason why the internal battery 52 can be efficiently charged by increasing the power efficiency is that the internal battery 52 is charged in series with the power receiving coil 51 without connecting a capacitor in parallel with the power receiving coil 51. This is because the power of the power receiving coil 51 can be output to the rectifier circuit 53 by connecting a capacitor to the capacitor. The circuit configuration in which the series capacitor 55 is connected to the power receiving coil 51 improves the power efficiency and suppresses the heat generation of the coil and the battery during charging, compared with the circuit configuration with a small transmission current connected to the power receiving coil, and the built-in battery 52 can be charged efficiently, promptly and safely.

The position detection controller 14 described above includes an impedance modulation capacitor 53 connected in parallel to the power receiving coil 51, a switching element 64 connecting the impedance modulation capacitor 53 to the power receiving coil 51, and turning on / off the switching element 64. And a control circuit 165 for controlling the switching element 164 to be turned on when the position of the power receiving coil 51 is detected. The battery built-in device 50 having this circuit configuration can transmit battery information using the impedance modulation capacitor 163, the switching element 164, and the control circuit 165 provided as the position detection controller 14. This is because the impedance load of the power receiving coil 51 can be changed by switching the switching element 164 on and off with a digital signal of battery information by the control circuit 165. Therefore, this battery built-in device 50 does not have a dedicated circuit for transmitting battery information, that is, with the same hardware, only the software for switching the switching element 64 on and off by the control circuit 65 is changed to change the battery information. Can be transmitted. The software can be stored in a memory provided in the control circuit 165. For this reason, this battery built-in apparatus 50 can transmit battery information to the charging stand 10 in an ideal state without increasing the manufacturing cost.

In this embodiment, whether the battery pack 50A is attached to the device main body 50B (the battery built-in device 50) or the battery pack 50A alone can be identified as follows. Then charge.
As disclosed in FIG.
The brass side output of the battery pack 50A is connected to the device main body 50B via a positive connection terminal +, and the negative side output is connected to a device main body 50B via a negative connection terminal −.
Further, the pack side mounting information terminal T acquires mounting information indicating the type of whether the battery pack 50A is a single unit or is mounted on the battery built-in device 50 (device main body 50B). In the example of FIG. 6, the pack side mounting information terminal T is connected to the input terminal of the control circuit 165 via the pull-up resistor R. On the other hand, the pack-side mounting information terminal T is connected to the ground terminal on the device body 50B side to form a short pin. For this reason, when the pack battery 50A is not connected to the device main body 50B, the pack-side mounting information terminal T detects the HIGH voltage via the pull-up resistor (pull-up state), and is connected on the other hand. The pack side mounting information terminal T is dropped to the ground, and the LOW voltage is detected. When the input terminal of the pack side mounting information terminal T is a HIGH voltage, the control circuit 165 determines that the battery pack is a single battery, and when the input terminal is a LOW voltage, the control circuit 165 determines that the battery pack 50A is mounted on the device main body 50B.
The determination of the mounting information regarding whether or not the battery pack 50A is a single battery is performed by the control circuit 165 detecting the pull-up / pull-down state as described above. A determination may be made. For example, the control circuit 165 may have a function of communicating with the device main body 50B (not shown), and may determine the mounting information based on the presence or absence of this communication.
Moreover, the load circuit 62 can be driven and transmitted from the power receiving coil 51 to the charging stand 10 using the determination result as mounting information. Thus, by adding the pack side mounting information terminal 70A, the mounting information of the battery pack 52 can be notified to the charging base 10 side.

Below, the detection of the metal foreign material in a present Example is demonstrated.
In non-contact charging, when a metal (or conductive) foreign material (for example, a metal clip of a stationery, a metal plate-shaped ruler, etc.) is interposed between the power transmission coil and the power reception coil or on the power transmission coil. Due to electromagnetic induction caused by magnetic lines of force transmitted from the power transmission coil, a current corresponding to eddy current flows through the metal foreign object, resulting in a high temperature. In addition, not only metallic (conductive) foreign matter but also insulating foreign matter (for example, a plastic plate ruler) is interposed between the upper plate 21 and the lower surface of the battery built-in device 50. Therefore, there is a detrimental effect on transmission efficiency. By detecting such a decrease in transmission efficiency, metallic (or conductive) and insulating foreign matters can be detected.
In the present embodiment, when a metal foreign object is placed on the upper surface plate 21, if a large foreign object is detected and a waveform different from the waveform of the echo signal is detected and identified as described above, the battery built-in device 50 is detected. The power supply can be stopped assuming that a coil other than the power receiving coil 51 (for example, a metal foreign object) is mounted. Further, when a metal foreign object is placed on the top plate 21, if it is small, the charging stand 10 cannot receive an authentication signal (= ID signal) such as a battery serial number as described above. Assuming that something other than the power receiving coil 51 (for example, a metal foreign object) is mounted, the power supply can be stopped.

The charging stand 10 charges the built-in battery 52 of the battery built-in device 50 by the following operation.
(1) When the battery built-in device 50 is placed on the upper surface plate 21 of the case 20, the position detection controller 14 detects the position of the battery built-in device 50 using the position detection coil 30.
(2) The position detection controller 14 that has detected the position of the battery built-in device 50 controls the moving mechanism 13 to move the power transmission coil 11 along the upper surface plate 21 with the moving mechanism 13, thereby Approach the power receiving coil 51.
(3) The power transmission coil 11 approaching the power reception coil 51 is electromagnetically coupled to the power reception coil 51 and carries AC power to the power reception coil 51.
(4) The battery built-in device 50 rectifies the AC power of the power receiving coil 51 and converts it into direct current, and charges the built-in battery 52 with this direct current.

Then, as described above, the transmission efficiency detection unit 84 detects the transmission efficiency from the ratio of charging power / input power. Since the power receiving coil 51 is accurately aligned on the power transmission coil 11, the transmission efficiency is good and stable. Normally, transmission efficiency of 60 to 65% can be obtained.
Whether the transmission efficiency output from the transmission efficiency detection unit 84 at the start of charging or during charging is equal to or less than a predetermined threshold value (for example, 50%) is calculated by the calculation unit 85 of the control circuit 80. Is determined. A value of 40 to 60% can be used as the predetermined value of such a threshold.
If the threshold value is less than or equal to the predetermined value, the metallic foreign matter is interposed between the power transmission coil 11 and the power receiving coil, and in this embodiment, the metallic foreign matter is interposed between the upper surface plate 21 and the lower surface of the battery built-in device 50. As a result of the stop signal from the calculation unit 85 of the control circuit 80,
The output power adjustment circuit 82 turns off the switching element 92 via the input circuit 93 and stops charging.
Instead, if the transmission efficiency is equal to or less than a predetermined rate of change (50/60 = 0.83 when changed from 65% to 50%), it can be determined that metal foreign matter is present. For such a change rate of transmission efficiency, a change between an initial value and a subsequent value, or a change in transmission efficiency at a predetermined time interval can be used.
In place of these, when the transmission efficiency decreases by a predetermined value or more (when the transmission efficiency decreases from 65% to 50%, it decreases by 15%), it can be determined that metal foreign matter is present. A value of 10 to 20% can be used as such a predetermined value. For such a decrease in transmission efficiency, a comparison between an initial value and a subsequent value, a comparison of transmission efficiency at a predetermined time interval, or the like can be used.
The predetermined value as described above is stored in the control circuit 80. However, a specific predetermined value is stored in the battery information detection circuit 59 of the battery built-in device 50 to be used, and this is used as the battery. Information can also be transmitted in the control circuit 80.

The charging stand 10 will describe the predetermined value of the above threshold for transmission efficiency when power is transmitted from the power transmission coil 11 to the power reception coil 51. A predetermined threshold value is set in advance according to the shape of the battery pack 50A, the distance between the power transmission coil 11 and the power reception coil 51, and the like. Here, when the battery pack 50A is a single unit as shown in FIG. 12 and when it is attached to the battery driving device 50 as shown in FIG. 13, the distances d1 and d2 between the power transmission coil 11 and the power reception coil 51 are as follows. Different. Specifically, when the battery pack is placed on the charging stand 10 alone, the distance d1 between the power transmission coil 11 and the power receiving coil 51 is about the case surface thickness (for example, 2.5 mm) of the charging stand 10. It is tied with a strong coupling coefficient. On the other hand, in a state in which the battery pack 52 is attached to the battery drive device 50, the distance d2 between the coils is increased by the amount of the battery lid for housing the battery pack 52 in the battery drive device 50, and the coupling coefficient is weakened. This difference reduces the transmission efficiency.

When charging the battery pack 52 of a lithium ion battery or a lithium polymer battery with constant voltage / constant current charging by regulating the maximum voltage and current, the battery pack 50A alone or the battery pack 50A is attached to the charging stand 10. Even when the battery built-in device 50 attached to the device main body 50B is normally mounted, the transmission efficiency also changes according to the magnitude of the charging current value. When the current value is small, the transmission efficiency is low, and when the current value is large and within an appropriate range, the transmission efficiency is high.
FIG. 14 shows a predetermined threshold value for each charging current value range whether the battery pack 50A is a single battery. In FIG. 14, the bold line is the predetermined threshold value of the battery pack, and the dotted line is the predetermined threshold value when the battery pack 50A is attached to the device main body 50B. The predetermined threshold value is changed or changed. That is, the predetermined threshold value depends on the mounting information and also depends on the magnitude of the charging current value.
Thus, by changing or changing the predetermined value of the threshold value, it is possible to appropriately determine the presence of foreign matter. In addition to the predetermined threshold value as shown in FIG. 14, such a predetermined value may be a predetermined value for each charging current value range, whether the battery pack 50 A is alone or not. Is possible. Such a predetermined value may be a value that does not depend on the charging current depending on the mounting information indicating whether the battery pack 50A is mounted on the device main body 50B, or the battery pack 50A depends on the charging current. It may be a value that does not depend on the mounting information on the state of being mounted on the main body 50B.
Such a predetermined value is specific to the battery pack 50A and the battery built-in device 50 to which the battery pack 50A is mounted. Therefore, the predetermined threshold value depends on the type of the battery pack 50A, the main device 50B, and the like. Can be set. The data is stored in advance in a memory in the control circuit 165 of the battery pack 50A.

And when mounted on the charging stand 10, when the charging is started, the control circuit 165 is in a state where the battery pack 50A alone or the battery pack 50A is mounted on the device main body 50B depending on the voltage of the input terminal of the pack-side mounting information terminal T During charging, the charging current and the like are repeatedly transmitted as battery information as described above during charging, and a predetermined threshold value corresponding to the measured charging current is shown in FIG. 14 is obtained from the table data corresponding to the predetermined threshold value shown in FIG. 14, and the load circuit 162 is operated by the control circuit 165 of the battery pack 50A, and the charging base 10 is connected via the power receiving coil 51, the power transmitting coil 11, and the detecting circuit 17. To the control circuit 80. As described above, the transmission of the predetermined value of the threshold may be in the same cycle as the charging current, or may be in a different cycle (for example, the charging current value is 250 mS and the predetermined value is 500 mS). By transmitting the measured charging current value and a predetermined value corresponding to the measured charging current value, there is no work such as calculating and calculating the predetermined value on the charging stand 10 side. The configuration and work burden are reduced.
In addition, the predetermined value of the threshold value is transmitted together with the charging current measured in this way, but instead,
A threshold value (for example, table data corresponding to a predetermined value of the threshold value shown in FIG. 14) for each charging current value range in a single or attached state at the start of charging is stored in the control circuit 80 of the charging base 10 in advance. May be communicated.

Thereafter, during charging, the transmission efficiency detection unit 84 detects the transmission efficiency from the ratio of charging power / input power, and the charging current value transmitted from the battery pack 50A as described above, and a predetermined threshold value corresponding thereto. Thus, whether or not the transmission efficiency is equal to or less than the predetermined value of the threshold value is calculated and determined by the calculation unit 85 of the control circuit 80. If it is below the predetermined value of the threshold value, the metal foreign matter is assumed to be interposed between the power transmission coil 11 and the power receiving coil, in this embodiment, between the upper surface plate 21 and the lower surface of the battery built-in device 50. In response to a stop signal from the arithmetic unit 85 of the control circuit 80, the output power adjustment circuit 82 turns off the switching element 92 via the input circuit 93 to stop charging. The abnormality can be appropriately displayed on an abnormality indicator (not shown) installed on the charging stand 10 to notify the user of the abnormality. As a result, as described above, the charging can be efficiently performed by preventing charging from being continued in a state where the transmission efficiency is reduced due to the space due to the foreign material, and the metal foreign material can prevent the temperature from becoming high and safety. Can be increased.
Further, as described above, the transmission unit 59 and the reception unit 89 described above can be used for transmission of various types of information.

When the position of the battery built-in device 50 is shifted from the position on the charging stand 10 due to an impact or the like, the battery information periodically transmitted as described above is transmitted via the reception coil 51 and the power transmission coil 11. Since the detection circuit 17 of the charging base 10 is not received, the calculation unit 85 of the control circuit 80 determines that there is no battery information, and the position detection controller 14 again performs the upper surface detection as described above. The position of the battery built-in device 50 placed on the plate 21 is detected, the power transmission coil 11 is moved closer to the power reception coil 51 and moved to an accurate position, and charging is performed.
As described above, in this embodiment, even when the position of the battery built-in device 50 is shifted from the position on the charging base 10, the power transmission coil 11 is again approached to the power reception coil 51 and is accurately positioned. Since it can be moved and charged, even at this position, the transmission efficiency is good and stable, so the presence of a foreign object can be determined from the transmission efficiency.

The charging stand 10 on the upper surface plate 21 on which a plurality of battery built-in devices 50 can be placed is fully charged by sequentially switching the batteries 52 of the plurality of battery built-in devices 50. The charging stand 10 first detects the position of the power receiving coil 51 of any of the battery built-in devices 50, makes the power transmitting coil 11 approach the power receiving coil 51, and fully charges the battery 52 of the battery built-in device 50. To do. When the battery 52 of the battery built-in device 50 is fully charged and the full charge detection circuit 17 receives the full charge signal, the position detection controller 14 is set to a second position different from the battery built-in device 50. The position of the power receiving coil 51 of the battery built-in device 50 is detected, and the moving mechanism 13 is controlled to bring the power transmitting coil 11 closer to the power receiving coil 51 of the second battery built-in device 50. In this state, power is transferred to the battery 52 of the second battery-equipped device 50, and the battery 52 is fully charged. Further, when the battery 52 of the second battery built-in device 50 is fully charged and the full charge detection circuit 17 receives the full charge signal from the second battery built-in device 50, the position detection controller 14 further performs the third operation. The power receiving coil 51 of the battery built-in device 50 is detected, the moving mechanism 13 is controlled to bring the power transmission coil 11 close to the power receiving coil 51 of the third battery built-in device 50, and the battery 52 of the battery built-in device 50 is moved. Fully charge. As described above, when the plurality of battery built-in devices 50 are set on the top plate 21, the battery built-in devices 50 are sequentially switched to fully charge the built-in battery 52. The charging stand 10 stores the position of the fully-charged battery device 50 and does not charge the battery 52 of the fully-charged battery device 50. When it is detected that the batteries 52 of all the battery built-in devices 50 set on the top plate 21 are fully charged, the charging stand 10 stops the operation of the AC power supply 12 and stops the charging of the batteries 52. Here, in the above embodiment, the charging is stopped when the battery 52 of the battery built-in device 50 is fully charged. However, the charging may be stopped when the battery 52 reaches a predetermined capacity. .

The above moving mechanism 13 moves the power transmission coil 11 in the X-axis direction and the Y-axis direction to move the power transmission coil 11 to a position closest to the power receiving coil 51. In the present invention, the movement mechanism is in the X-axis direction. The power transmission coil is moved in the Y-axis direction and the position of the power transmission coil is not specified as a structure for approaching the power reception coil, and the power transmission coil can be moved in various directions to approach the power reception coil.

The charging stand according to the present invention can be suitably used not only for charging a mobile phone or a portable music player but also for charging an assist bicycle or an electric vehicle.

DESCRIPTION OF SYMBOLS 10 ... Charging stand 11 ... Power transmission coil 12 ... AC power supply 13 ... Movement mechanism 14 ... Position detection controller 15 ... Core 15A ... Cylindrical part 15B ... Cylindrical part 16 ... Lead wire 17 ... Detection circuit 20 ... Case 21 ... Top plate 22 ... Servo motor 22A ... X-axis servo motor 22B ... Y-axis servo motor 23 ... Screw rod 23A ... X-axis screw rod 23B ... Y-axis screw rod 24 ... Nut material 24A ... X-axis nut material 24B ... Y-axis nut material 25 ... Belt 26 ... guide rod 27 ... guide part 30 ... position detection coil 30A ... X-axis position detection coil 30B ... Y-axis position detection coil 31 ... detection pulse generation circuit 32 ... reception circuit 33 ... identification circuit 34 ... switching circuit 35 ... limiter circuit 36 ... A / D converter 50 ... Electric Built-in device 50A ... pack battery 50B ... device main body 51 ... receiving coil 52 ... battery 53 ... capacitor 54 ... parallel resonant circuit 55 ... diode 56 ... smoothing capacitor 57 ... rectifier circuit 58 ... charge control circuit 59 ... transmitter (battery information detection circuit) )
64 ... Position detection controller 73 ... Identification circuit 77 ... Memory circuit 80 ... Control circuit 81 ... Frequency adjustment circuit 82 ... Output power adjustment circuit 83 ... Charging power detection unit 84 ... Transmission efficiency detection unit 85 ... Calculation unit 87 ... Input power detection Numeral 89 ... Receiving unit 90 ... Rectifier circuit 91 ... DC / AC inverter 92 ... SWI · BR> B-ching element 93 ... Input circuit 99 ... Commercial power supply 130 ... Position detection coil 130A ... X-axis position detection coil 151 ... Receiving coil 155 ... Series capacitor 161 ... Modulation circuit 164 ... Switching element 162 ... Load circuit 165 ... Control circuit + ... Positive connection terminal -... Negative connection terminal T ... Pack side mounting information terminal

Claims

The battery pack (50A) with a built-in battery (52) charged with the power carried by the power receiving coil (51) is charged alone, or the battery pack (50A) is attached to the battery built-in device (50). Charging base (10) for charging
A charging stand (10) comprising a power transmission coil (11) connected to an AC power source (12) and carrying electromotive force to the power reception coil (51),
The AC power supply (12) includes a control circuit (80) having a transmission efficiency detection unit (84) for detecting transmission efficiency for conveying power to the battery built-in device (50),
In the control circuit (80), the transmission efficiency is compared with a predetermined value to determine whether there is a foreign object between the charging base and the battery built-in device (50) or the battery pack (50A), and the battery pack (50A) is a predetermined value that depends on mounting information indicating a type of whether it is a single unit or is mounted on the battery-powered device 50, and / or depends on the magnitude of the charging current value. Characteristic charging stand.
The charging stand according to claim 1, wherein in the control circuit (80), when the transmission efficiency is equal to or lower than a predetermined value, it is determined that a foreign object exists between the charging stand and the battery built-in device (50).
The transmission efficiency detection unit (84) is a value obtained by multiplying the power consumption or current value consumed by the AC power supply (12), the voltage value, and the charging power or current charging the battery (52) of the battery built-in device (50). The charging stand according to claim 1, wherein a transmission efficiency is detected from a ratio of charging power to power consumption by detecting a value obtained by multiplying a voltage and a voltage.
The charging stand according to claim 1, wherein a predetermined value depending on a magnitude of the charging current value together with the charging current value measured in the pack battery (50A) is also transmitted from the pack battery (50A) to the charging stand.
The charge current value measured in the battery pack (50A) and a predetermined value that depends on the mounting information and depends on the magnitude of the charge current value are also transmitted from the battery pack (50A) to the charging stand. Charging stand described.
In the control circuit (80), the transmission efficiency is compared with a predetermined value to determine whether there is a foreign object between the charging base and the battery built-in device (50) or the battery pack (50A), and the charging is stopped. The charging stand according to claim 1.
The battery pack (50A) that is installed in the battery built-in device (50) and the battery charger (50A) that can be charged by itself or the battery pack (50A) that is charged in the battery-equipped device (50). (10)
Transmission efficiency depending on the mounting information indicating the type of whether the battery pack (50A) is a single unit or mounted on the battery-powered device (50) and / or depends on the magnitude of the charging current value A battery pack (50A) that stores a predetermined value of
A charging base (10) of a battery built-in device (50) including a battery (52) to be charged with electric power conveyed to the power receiving coil (51), and connected to an AC power source (12), the power receiving coil (51) is provided with a power transmission coil (11) for conveying electromotive force,
The AC power supply (12) includes a control circuit (80) having a transmission efficiency detection unit (84) for detecting transmission efficiency for conveying power to the battery built-in device (50), and in the control circuit (80), the transmission Comparing the efficiency with the predetermined value, and determining whether there is a foreign object between the charging stand (10) and the battery built-in device (50) or the battery pack (50A), and charging the battery pack Stand.
A battery pack (50A) mounted on the battery built-in device (50), which is charged by the battery pack (50A) alone by the charging stand (10) or mounted in the battery built-in device 50 (50A). ) Is charged
The power receiving coil (51) is charged with the electric power conveyed to the power receiving coil (51) by the charging stand (10) provided with the power transmitting coil (11) connected to the AC power source (12) and carrying the electromotive force to the power receiving coil (51). The battery pack (50A) containing the battery (52) is charged,
The AC power source (12) of the charging stand (10) includes a control circuit (80) having a transmission efficiency detection unit (84) for detecting transmission efficiency for conveying power to the battery built-in device (50), and the control circuit ( 80), the transmission efficiency is compared with a predetermined value to determine whether foreign matter exists between the charging stand (10) and the battery built-in device (50) or the battery pack (50A). Depends on mounting information indicating the type of battery (50A), whether the battery pack (50A) is a single unit or mounted on the battery-powered device (50), and / or the magnitude of the charging current value A pack battery characterized in that the predetermined value of the transmission efficiency depending on the battery is stored.
The pack according to claim 7, wherein a predetermined value depending on the magnitude of the charging current value together with the charging current value measured in the pack battery (50A) is also transmitted from the pack battery (50A) to the charging stand (10). battery.
The charging current value measured in the battery pack (50A) and a predetermined value that depends on the mounting information and depends on the magnitude of the charging current value are also transmitted from the battery pack (50A) to the charging stand. The battery pack described.